if you walked as an adult for half an hour a day, you know, i walk here across central park, say, to cnn, i feel like it's a pretty good exercise walking at a reasonable pace. is that enough to be fit? >> perfect amount. the goal -- >> i'm basically a perfect specimen then? >> i have your lab studies here. >>dy this. >> don't look at them yet. we'll get to these. >> it's enough. after a two-week break, not going to be good. british beer. also turkey. and lots of rum. wine. it's going to be ghastly. we'll come to that later. >> we'll tease that reality. i have seen the tests and talking about them because you're mr. america in many ways. despite your british okay krentd. you know, physical activity, looking around the world, places where people live a long time, it is not about going to the gym every day and an arduous two-hour workout once in a while but about 30 minutes of activity that brings your heart rate up a little bit. so walking to work is about the best and smartest thing to do. also, you don't have to do a workout at the end of the day. you have your activity. people who have